Judge Lord Turnbull said the scam is "an episode of shame" for the pelagic fishing industry.

He said it was a "cynical and sophisticated" operation which had the "connivance of a number of different interested parties".

The Daily Record recently revealed the scale of the scam.

The trawler men behind the “black fish” swindle heaped gifts on family and friends.

They also used some of the cash to improve their fleets so they could catch even more fish.

The 17 skippers admitted landing illegal catches worth £47.5million.

But sources close to the Shetland fishing community suggested the extent of the scam could be much bigger.

One said: “The figure is just the tip of the iceberg. One of those boats could land that in a year and there is more than one vessel and skipper involved.

“It doesn’t require Carol Vorderman to work it out.

“I don’t think we will ever know how much they made and where all that money went.”

The skippers have already been hit with massive confiscation orders of the kind normally used on drug barons.

Pre-sentencing hearings at the High Court in Edinburgh heard that one skipper had £100,000 in a non-interest bearing current account.

One had a second property in France, one had a holiday home in Spain and another bought a £30,000 Volvo.

One commentator said: “These offences took place almost 10 years ago and many of the skippers are now in their 60s and retired.

“One said he had a pension of £68,000, another had bought his daughter a house. But they’re beyond the stage of flaunting their riches like football stars.”

During proceedings, Gordon Jackson QC said the confiscation of illegal profits, the cut in catch quotas and the costs involved meant some of the skippers actually lost out through the scam.

He added: “Every penny has been paid back. They shot themselves in the foot. They have ended up worse off than had they not done it in the first place.”

The court heard that at Shetland Catch, officials from the Scottish Fisheries Protection Agency monitored catch sizes on computer screens which had been altered to show lower weights. The true size of the landings were shown in another room.

The skippers admitted breaching the Sea Fishing (Enforcement of Community Controls Measures) (Scotland) Order of 2000 and the Fisheries Act 1981. They cannot be jailed but they do face heavy fines.

Since the scam was uncovered, tough measures have been brought in to prevent illegal catches.

For a full breakdown of the fines, go to page two.

Hamish Slater, 53, and Alexander Masson, 66, both from Fraserburgh, were fined a respective £80,000 and £50,000, while Alexander Wiseman, 60, from Banff, was also fined £50,000.

Another 13 men from Shetland were fined for their role in the scam.

Robert Polson, 48, was fined £70,000; John Irvine, 68, was fined £80,000; William Williamson, 65, was fined £45,000; Laurence Irvine, 66, was fined £80,000; and David Hutchison, 66, was fined £40,000, as was 56-year-old Thomas Eunson.

Both Allister Irvine, 63, and Gary Williamson, 52, were fined £35,000; and George Henry, 60, was fined £12,000.

John Stewart, 57, was ordered to pay £15,000, while George Anderson, 56, must pay £12,000.

Colin Leask, 39, and Allen Anderson, 55, were each fined £3,000

A £70,000 fine was imposed on Victor Buchini, 51, from Poulton-le-Fylde in Lancashire.

The company Alexander Buchan was fined £240,000 for helping the vessel masters land the undeclared fish.

The 17 skippers were earlier ordered to pay the following sums under the Proceeds of Crime Act: